In the face of the increasing demand for a variety of high speed digital data communication services (such as, but not limited to HDSL, ADSL and SDSL), telecommunication service providers are continually seeking ways to optimize utilization of their very substantial existing copper plant, which was originally installed for the purpose of carrying nothing more than conventional analog (plain old telephone service or POTS) signals. Associated with this expanded utilization of the telephone line pairs is the need to verify end-to-end connections of a respective wireline pair. It is essential that the technique employed be non-intrusive to the line under test, which could be an unused spare, an idle line connected to subscriber equipment, or a busy line (namely, one carrying analog and/or digital signals). This non-intrusive requirement is especially paramount if the line is carrying digital data traffic.